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79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Brooklyn Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Brooklyn: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Brooklyn
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Brooklyn
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
4
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
5
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
6
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Haddam Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Haddam: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Haddam
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Haddam
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
Statewide Bacteria TMDL
Bacteria Chatfield Hollow Brook
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/chatfieldhollowbrook5105.pdf
Statewide Bacteria TMDL
Bacteria Connecticut River
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/connecticutriver4000.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
4
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
5
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
6
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Killingly Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Killingly: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Killingly
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Killingly
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
4
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
5
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
6
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Mansfield Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Mansfield: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Mansfield
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Mansfield
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
Statewide Bacteria TMDL
Bacteria Skungamaug River / Crandall Pond
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/skungamaugriver3106.pdf
Statewide Bacteria TMDL
Bacteria Willimantic River, Eagleville Brook, and Cedar Swamp Brook
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/willimanticriver3100.pdf
A TMDL Analysis for Eagleville Brook, Mansfield, CT
Multiple pollutants
Eagleville Brook http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/eaglevillefinal.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
4
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
5
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
6
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of New Hartford Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of New Hartford: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of New Hartford
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of New Hartford
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
Statewide Bacteria TMDL
Bacteria Farmington River (02) / Munniskunk Brook / Owens Brook / Russell Brook / Minister Brook
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/farmingtonriver4300.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
4
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
5
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
6
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Plainfield Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Plainfield: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Plainfield
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Plainfield
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
4
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
5
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
6
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Sprague Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Sprague: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Sprague
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Sprague
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound and contributing watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
Statewide Bacteria TMDL
Bacteria Shetucket River and Obwebetuck Brook
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/shetucketriver3800.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
4
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
5
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
6
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
7
8
1
79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer
Factsheet: Town of Willington Water Quality
This document was created for each town that will be covered by the proposed Small Municipal
Separate Storm Sewer System (MS4) General Permit. In addition to the 113 towns covered by
the current MS4 permit, the new permit would add 8 new towns to this list as “Tier 1” MS4s. All
other towns in the state (49 towns) are proposed to be designated as “Tier 2” MS4s with reduced
requirements for compliance. What follows is information on how stormwater can affect water
quality in streams, rivers and Long Island Sound. This factsheet is intended to help you interpret
any stormwater monitoring results that you may have or may collect and assist you in
compliance with the MS4 program.
Water Quality in Connecticut
Surface waters are important resources that support numerous uses, including water supply,
recreation, fishing, shellfishing and sustaining aquatic life. Water quality conditions needed to
support these uses are identified within the Connecticut Water Quality Standards (WQS). In
order to protect and restore these uses, we need acceptable environmental conditions (physical,
chemical and biological) to be present within surface waters.
To assess and track water quality conditions, CT DEEP conducts monitoring across the State.
The data is synthesized into a biennial state water quality report called the Integrated Water
Quality Report. Currently, specific water quality monitoring in the state encompasses about 50%
of rivers, 47% of lakes, and 100% of estuary/coastline. In addition, CT DEEP may have
information about certain land uses or discharges which could indicate a potential for water
quality to be impacted, even if the waterbody has not been fully monitored and assessed.
To find more detailed information on water quality in your town, please see the Integrated Water
Quality Report (IWQR) on the CT DEEP website at http://www.ct.gov/dep/iwqr. Information on
water quality within your town is also presented on the maps included in this fact sheet.
Impacts of Impervious Cover on Water Quality
Impervious cover (IC) refers to hard surfaces across the landscape such as roads, sidewalks,
parking lots and roofs. Studies have focused on the amount of hard surfaces to evaluate the impacts
of stormwater runoff from these hard surfaces on water quality and found that IC affects both the
quantity and quality of stormwater. IC forces rain to run off the land, carrying pollutants quickly
and directly to lakes and streams instead of soaking into the ground and being filtered by the soil.
For more information on impervious cover, please see the CT DEEP web page (link) and EPA’s
web page (EPA IC Link ).
2
In general, the higher the percentage of IC in a watershed, the poorer the surface water quality.
Research in Connecticut strongly suggests that aquatic life will be harmed when the IC within a
watershed exceeds 12%. Stormwater pollution from IC is a likely cause of impairment for these
waterbodies.
Town of Willington: Impervious Cover Data
This chart shows the amount of area within your town that contains IC. Data is grouped by acres
and percent IC. While all levels of IC can contribute stormwater to streams, it is important to
note that land with IC greater than 12% in town is likely to be contributing enough stormwater to
streams to have a negative impact on water quality.
Towns should aim to make stormwater improvements in areas with IC greater than 12% in an
effort to reduce the amount of stormwater pollution reaching surface waters which will protect
and improve water quality.
For more information on areas of impervious cover within your town, please see the maps at the
end of this factsheet.
Amounts of Impervious Cover within the Town of Willington
3
Pollution Reduction
Waterbodies often can handle a certain amount of pollutants and still maintain good water quality.
However, impaired waterbodies have too much pollution impacting their water quality and
therefore the streams do not support all uses for the waterbody. Total Maximum Daily Loads
(TMDLs) are pollution reduction budgets developed for impaired waterbodies in order to meet
water quality. If the pollution budget is achieved through the recommended pollution reduction
measures, then the waterbody is expected to meet water quality. CT DEEP also supports impaired
waters restoration through watershed based plans (see link) which provides more specific non-
point source pollution control measures. The following TMDLs or pollution reduction strategies
have been developed and apply to areas within your town.
TMDLs or Strategies Applicable to the Town of Willington
Name of TMDL or Strategy
Pollutant Waterbody Name
Link
A TMDL Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound
Nitrogen Long Island Sound & Contributing Watersheds
http://www.ct.gov/deep/lib/deep/water/lis_water_quality/nitrogen_control_program/tmdl.pdf
Northeast Regional Mercury TMDL
Mercury All CT Inland waters
http://www.ct.gov/deep/lib/deep/water/tmdl/tmdl_final/ne_hg_tmdl.pdf
Interim Phosphorus Reduction Strategy
Phosphorus Certain CT Inland waters
http://www.ct.gov/deep/lib/deep/water/water_quality_standards/p/interimmgntphosstrat_042614.pdf
Statewide Bacteria TMDL
Bacteria Skungamaug River / Crandall Pond
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/skungamaugriver3106.pdf
Statewide Bacteria TMDL
Bacteria Willimantic River, Eagleville Brook, and Cedar Swamp Brook
http://www.ct.gov/deep/lib/deep/water/tmdl/statewidebacteria/willimanticriver3100.pdf
For more information on these TMDLs or strategies please go to our website
http://www.ct.gov/deep/tmdl .
4
Stormwater Quality Monitoring
Although your town may not be required to monitor stormwater outfalls under the draft MS4
permit, regular monitoring for targeted pollutants in stormwater provides an indication of potential
for water quality impacts and helps identify sources and unlawful discharges. Annual monitoring
of twelve chemical parameters at 6 locations from different areas of town has been a requirement
for towns covered by the current MS4 permit since 2004. CT DEEP uses that information to
evaluate the quality of stormwater and the potential for impacts to surface waters as well as to
make sure that stormwater is managed properly. A few parameters currently monitored by MS4
towns are described below.
Bacteria
Escherichia coli (E. coli) is a bacteria that lives in the intestines of humans and other warm-
blooded animals and is used to indicate the presence of fecal matter in surface waters. Some
strains of E. coli and other pathogens found in fecal material cause serious illness in people
coming in contact with it. For this reason, high amounts of bacteria will cause authorities to
close beaches for swimming.
Bacteria is measured as the number of colony forming units, or CFU, per 100 ml of water. To
support recreational uses of surface waters, the CT DEEP Water Quality Standards indicate that
the average amount of E. coli found in a freshwater water body should be less than 126 CFU/100
mL and that a single sample tested for E. coli should be less than 235 CFU/100 mL at a
designated swimming area and less than 410 CFU/100 mL in other areas. Monitoring for E. coli
is currently required in the MS4 permit.
Enterococci is another bacteria used to indicate the presence of fecal material in salt water
environments. For recreation in salt water the Water Quality Standards indicate that average
amount of Enterococci should be less than 35 CFU/100 mL in a designated swimming area and
that a single sample tested for Enterococci should be less than 104 CFU/100 mL and in all other
areas less than 500 CFU/100 mL. These targets have been included in the statewide bacteria
TMDLs. In the Draft MS4 permit, Tier 1 MS4s with E. coli results higher than 235 CFU/100
mL at a designated swimming area or greater than 410 CFU/100 mL in other areas requires a
follow-up investigation. Individual stormwater sample results that exceed the applicable single
sample maximum value for bacteria could impact water quality, so the associated outfalls should
be evaluated for additional stormwater management.
Total Suspended Solids
Total Suspended Solids (TSS) is a measurement of the amount of solids (including sand and silt)
found in the stormwater sample. High concentrations of TSS can lower water quality in the
receiving stream by transporting various pollutants to the waterbody where they can directly affect
aquatic life or affect aquatic life by absorbing light, reducing photosynthesis, and by making the
water warmer. TSS can also clog fish gills and smother fish eggs and suffocate the organisms that
fish eat. TSS comes from erosion and is found in agricultural, urban and industrial runoff. TSS
can be reduced by protecting land from erosion and allowing stormwater time to settle before
discharging to surface waters.
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Currently, there is not a water quality based target for TSS in stormwater but TSS is a general
indicator of water quality and, lower amounts of TSS are better. The average MS4 stormwater
result reported for TSS by all towns covered by this permit is 48 mg/L. If future stormwater
monitoring completed by your town finds areas that have elevated TSS, these may be places to
consider additional stormwater management efforts.
Total Nitrogen
Nitrogen is an important nutrient in marine and estuarine waters such as Long Island Sound, as
well as a concern in fresh water lakes and rivers. High amounts of nitrogen can lead to excessive
growth of water plants and algae, which then reduces the amount of oxygen available to living
things in these waters. Unlawful discharges, animal waste, failing septic systems, leaves, litter and
fertilizers are common sources of high nitrogen in stormwater. Responsible use of fertilizers,
maintaining septic systems and proper disposal of pet waste will help reduce nitrogen in
stormwater.
The TMDL for Long Island Sound requires a 10% reduction of nitrogen in stormwater
discharges to prevent low oxygen conditions in Long Island Sound. Each town should be
working to reduce the amount of nitrogen in their stormwater to address this issue. Under the
current draft MS4 permit, any Tier 1 MS4s with a result for total nitrogen greater than 2.5 mg/L
will require a follow-up investigation. If you find areas within your town, which have elevated
nitrogen, these locations may be places to consider additional stormwater management activities.
Total Phosphorus
Phosphorus is an important nutrient necessary for growth in plants and animals in freshwater.
Too much phosphorus in the water can throw off the balance of aquatic ecosystems causing
excessive growth of water plants and algae blooms, which reduces the amount of oxygen in the
water potentially harming the fish. Sometimes these algae blooms can contain toxic forms of
algae which are harmful to people and animals that come into contact with it. Sources of high
phosphorus can be unlawful discharges, fertilizers, litter, leaves, erosion and animal waste.
CT DEEP is actively working with many towns to reduce the amount of phosphorus reaching
Connecticut’s streams and rivers. Under the current draft MS4 permit, any Tier 1 MS4 with a
total phosphorus result greater than 0.3 mg/L will require a follow-up investigation. If you find
areas of your town that have elevated levels of phosphorus in the stormwater, these locations are
good places to develop additional stormwater controls.
Turbidity
Turbidity measures the clarity of the stormwater sample. It measures how much material (soil,
algae, pollution, microbes etc.) is suspended in the sample. High turbidity lowers the water
quality of a surface water by blocking sunlight for the plants and makes food harder for the fish
to find and may be an indication of a higher amounts of other pollution in the water. Surface
waters with high turbidity are visually less appealing for recreational use. High turbidity can be
caused by erosion, failing septic systems, decaying plants or animals, and excessive algae
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growth. Turbidity is reported in Nephelometric Turbidity Units (NTU), which is related to how
easily light passes through the water sample.
The Water Quality Standards have a criterion that indicates turbidity should not to exceed 5 NTU
above ambient levels. In the draft MS4 permit, any Tier 1 MS4 with a turbidity result greater
than 5 NTU over in-stream conditions will require a follow-up investigation. While there is not a
fixed statewide criterion for turbidity, lower results are better for the health of the surface waters
in town. If you find areas within your town with higher levels of turbidity in stormwater, these
would be good places to develop additional stormwater controls.
Town Maps
The following maps were created to show the impervious cover (IC) in your town as well as the
water quality in the rivers, streams, lakes and estuaries in and around your town.
Impervious Cover on the Town Maps
IC is shown in red on the maps. Dark red areas indicate a higher percentage of IC, lighter red
areas have less IC, while the grey areas indicate very little or no IC.
Water Quality on the Town Maps
Separate maps are provided for the different uses of the waterbodies such as Aquatic Life Uses,
Recreation, and Shellfishing (in coastal towns). The waterbodies are colored to show the health
of the waterbody. Green means that the waterbody meets the water quality requirements to fully
support the specified use. Yellow means that water quality is poor and that the specified use is
not met. Blue means that there is not enough information to know whether or not water quality
is good or bad to support the specified use. Additionally, a small map is provided on the left side
of each larger map to show which watersheds are within your town.
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